Many methods have been devised to warn people against being struck, pinched, crushed or otherwise harmed by vehicles and mobile equipment. Unfortunately, the systems that have been devised to help protect people and property in these industrial operations, such as proximity detection and collision avoidance systems, have usually not been very effective. A new proximity detection system was developed and successfully demonstrated for use on continuous miners, as disclosed in U.S. Pat. No. 7,420,471 (the '471 patent), U.S. Pat. No. 8,169,335 (the '335 patent) and U.S. Pat. No. 8,232,888 (the '888 patent), and US patent publications 2009/0322512 (the '512 publication), 2010/0271214 (the '214 publication) and 2013/0038320 (the '320 publication), which patents and publications are herein referred to collectively as the “Frederick patents,” the disclosures of which are incorporated herein by reference in their entireties.